Yamaha V9958

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Yamaha V9958
Yamaha V9958(ceramic package)

The Yamaha V9958 is a Video Display Processor (VDP) used in MSX 80s home computers. More specifically, the MSX2+, MSX turbo R and the "TIM" upgrade to the TI-99/4A.

The Yamaha V9958, also known as MSX-Video, is the successor of the Yamaha V9938. It was clearly conceived not to be a very major upgrade to its predecessor, which hampered its adoption. The main new features are three graphical YJK modes (with up to 19268 colours) and horizontal scrolling registers.

Specifications[edit]

  • Video RAM: 128 KB + 64 KB of expanded VRAM
  • Text modes: 80 x 24 and 32 x 24
  • Resolution: 512 x 212 (4 or 16 colours out of 512) and 256 x 212 (16, 256, 12499 or 19268 colours)
  • Sprites: 32, 16 colours, max 8 per horizontal line
  • Hardware acceleration for copy, line, fill, etc.
  • Interlacing to double vertical resolution
  • Horizontal and vertical scroll registers

Detailed specifications[edit]

For detailed specifications, please refer to the Yamaha V9938 page, with the following additions:

  • Horizontal scrolling registers
  • YJK graphics modes (similar to YUV)
    • G7 + YJK + YAE: 256 x 212, 12499 colours + 16 colour palette
    • G7 + YJK: 256 x 212, 19268 colours
  • Ability to execute hardware accelerated commands in non-bitmap screen modes
  • Lightpen and mouse functions from V9938 were removed

MSX-specific terminology[edit]

On MSX, the screen modes are often referred to by their assigned number in MSX-Basic. This mapping is as follows:

Basic mode VDP mode MSX system
Screen 0 (width 40) T1 MSX 1
Screen 0 (width 80) T2 MSX 2
Screen 1 G1 MSX 1
Screen 2 G2 MSX 1
Screen 3 MC MSX 1
Screen 4 G3 MSX 2
Screen 5 G4 MSX 2
Screen 6 G5 MSX 2
Screen 7 G6 MSX 2
Screen 8 G7 MSX 2
Screen 10 G7 with YJK and YAE MSX 2+ and tR
Screen 11 G7 with YJK and YAE MSX 2+ and tR
Screen 12 G7 with YJK MSX 2+ and tR